diff options
| author | Kairui Song <kasong@tencent.com> | 2022-08-02 01:31:55 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-11 20:25:51 -0700 |
| commit | 2fd86a07c9ac50dfbc5eef3c69ef6e5d370f3b28 (patch) | |
| tree | 8ecfcf8df7387748a871e9396b05a76d33c0f49d /mm/util.c | |
| parent | e933dc4a07b36b835f8ad7085e17cc21ed869051 (diff) | |
mm/util: reduce stack usage of folio_mapcount
folio_test_hugetlb() will call PageHeadHuge which is a function call,
and blocks the compiler from recognizing this redundant load.
After rearranging the code, stack usage is dropped from 32 to 24, and
the function size is smaller (tested on GCC 12):
Before:
Stack usage:
mm/util.c:845:5:folio_mapcount 32 static
Size:
0000000000000ea0 00000000000000c7 T folio_mapcount
After:
Stack usage:
mm/util.c:845:5:folio_mapcount 24 static
Size:
0000000000000ea0 00000000000000b0 T folio_mapcount
Link: https://lkml.kernel.org/r/20220801173155.92008-1-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/util.c b/mm/util.c index c9439c66d8cf..f0cf92b8826e 100644 --- a/mm/util.c +++ b/mm/util.c @@ -850,10 +850,10 @@ int folio_mapcount(struct folio *folio) return atomic_read(&folio->_mapcount) + 1; compound = folio_entire_mapcount(folio); - nr = folio_nr_pages(folio); if (folio_test_hugetlb(folio)) return compound; ret = compound; + nr = folio_nr_pages(folio); for (i = 0; i < nr; i++) ret += atomic_read(&folio_page(folio, i)->_mapcount) + 1; /* File pages has compound_mapcount included in _mapcount */ |